A 709-50 has good strength to weight ratios and is conducive to bridge and support applications. The enhanced strength allows for thinner sections and yield the same support over heavier uses of mild steel.
Note - Where "-" appears in this table, there is no requirement.
|Grade||Plate Thickness, in. [mm]||Structural Shape Flange or Leg Thickness, in. [mm]||Yield Point or Yield Strength, B ksi [MPa]||Tensile Strength, ksi [MPa]||Min. Elongation, %||Reduction of AreaC,D min,%|
|Plates and BarsC,E||ShapesE|
|8 in. or 200 mm||2 in. or 50 mm||8 in. or 200 mm||2 in. or 50 mm|
|36 ||to 4 , incl||to 3 in. [75 mm], incl||36  min||58-80 [400-550]||20||23||20||21||-|
|over 3 in. [75 mm]||36  min||58  min||-||-||20||19||-|
|50 ||to 4 , incl||all||50  min||65  min||18||21||18||21F||-|
|50S [345S]||G||all||50-65 [345-450]H,I||65 H min||-||-||18||21||-|
|50W [345W] and HPS 50W [HPS 345W]||to 4, incl||all||50  min||70 ||18||21||18||21J||-|
|HPS 70W [HPS 485 W]||to 4, incl||G||70  minB||85-110 [585-760]||-||19K||-||-||-|
|HPS 100W [HPS 690 W]||to 2½, incl||G||100  minB||110-130 [760-895]||-||18K||-||-||L|
|over 2½ to 4 [65 to 100], inclM||G||90  minB||100-130 [690-895]||-||16K||-||-||L|
ASee specimen orientation and preparation subsection in the Tension Test section of Specification A6/A6M.
BMeasured at 0.2% offset or 0.5% extension under load as described in Section 13 of Test Methods A370.
CElongation and reduction of area not required to be determined for floor plates.
DFor plates wider than 24 in. [600 mm], the reduction of area requirement, where applicable, is reduced by five percentage points.
EFor plates wider than 24 in. [600 mm], the elongation requirement is reduced by two percentage points. See elongation requirement adjustments in the Tension Tests section of Specification A6/A6M.
FElongation is 2 in. or 50 mm: 19% for shapes with flange thickness over 3 in. [75 mm].
HThe yield to tensile ratio shall be 0.87 or less for shapes that are tested from the web location; for all other shapes, the requirement is 0.85.
IA maximum yeild strength of 70 ksi [480 MPa] is permitted for structural shapes that are required to be tested from the web location.
JFor wide flange shapes with flange thickness over 3 in. [75 mm], elongation in 2 in., or 50 mm of 18% minimum applies.
KIf measured on the Fig.3 (Test Methods A370) 1½ in. [40 mm] wide specimen, the elongation is determined in a 2 in. or 50 mm gage length that includes the fracture and shows the greatest elongation.
L40% minimum applies if measured on the Fig 3 (Test Methods A370) 1½ in. [40 mm] wide specimen; 50% minimum applies if measured on the Fig. 4 (Test Methods A370) ½ in. [12.5 mm] round specimen.
MNot applicable to Fracture Critical Tension Components (see Table 9).